The present invention relates generally to the field of methods and medical devices for modulating cardiac muscle activity and contractility and for cardiac pacing and more specifically to the field of methods for controlling the delivery of non-excitatory excitable tissue control (ETC) signals to the heart.
Excitable tissue control (ETC) devices are devices which modulate the activity of excitable tissues by application of non-excitatory electrical field signals to the excitable tissue through suitable electrodes in contact with the tissue. For example, ETC devices which are also known in the art as cardiac contractility modulation (CCM) devices may be used, inter alia, to increase or decrease the contractility of cardiac muscle in vitro, in vivo and in situ., as disclosed in detail in PCT application PCT/IL97/00012 (International Publication Number WO 97/25098) to Ben-Haim et al., titled xe2x80x9cELECTRICAL MUSCLE CONTROLLERxe2x80x9d, incorporated herein by reference. Other methods and applications of ETC devices are disclosed in PCT application PCT/IL97/00231 (International Publication Number WO 98/10828) titled xe2x80x9cAPPARATUS AND METHOD FOR CONTROLLING THE CONTRACTILITY OF MUSCLESxe2x80x9d to Ben Haim et al., incorporated herein by reference, PCT application PCT/IL97/00232 (International Publication Number WO 98/10829) titled xe2x80x9cDRUG-DEVICE COMBINATION FOR CONTROLLING THE CONTRACTILITY OF MUSCLESxe2x80x9d to Ben Haim et al., incorporated herein by reference and PCT application PCT/IL97/00233 (International Publication Number WO 98/10830) titled xe2x80x9cFENCING OF CARDIAC MUSCLESxe2x80x9d to Ben Haim et al., incorporated herein by reference, PCT application PCT/IL97/00235 (International Publications Number WO 98/10831) to Ben Haim et al., titled xe2x80x9cCARDIAC OUTPUT CONTROLLERxe2x80x9d, incorporated herein by reference.
Co-Pending U.S. patent application to Darvish et al., Ser. No. 09/260,769, titled xe2x80x9cCONTRACTILITY ENHANCEMENT USING EXCITABLE TISSUE CONTROL AND MULTI-SITE PACINGxe2x80x9d, filed Mar. 2, 1999 and assigned to the common assignee of the present application, the entire specification of which is incorporated herein by reference, discloses a method for multi-site cardiac pacing combined with ETC signal delivery for cardiac output enhancement.
Further applications of the ETC including devices combining cardiac pacing and cardiac contractility modulation are disclosed in PCT Application, International Publication No. WO 98/10832, titled xe2x80x9cCARDIAC OUTPUT ENHANCED PACEMAKERxe2x80x9d to Ben Haim et al., co-assigned to the assignee of the present application. Such ETC devices function by applying to selected cardiac segments non-excitatory electrical signals of suitable amplitude and waveform, appropriately timed with respect to the heart""s intrinsic electrical activity or with respect to paced cardiac electrical activity. The contraction of the selected segments can be modulated to increase or decrease the stroke volume of the heart. The timing of the ETC signals must be carefully controlled since application of the ETC signal to the myocardium at inappropriate times may be arrhythmogenic. The ETC signal must therefore be applied to the selected cardiac segment within a defined time interval during which the selected cardiac segment will not be stimulated by the ETC signal.
As disclosed in International Publication No. WO 98/10832, the ETC signal may be timed relative to a trigger signal which is also used as a pacing trigger, or may be timed relative to locally sensed depolarizing electrogram signals.
Timing of the delivery of ETC signals relative to the time of detection of locally sensed electrogram signals may present certain practical problems. For example, triggering of the ETC signal by any locally detected depolarizing signals irrespective of the time of detection of the depolarizing signal within the cardiac beat cycle, may increase the probability of spurious detection of noise signals or of ectopic beats such as premature ventricular contractions (PVCs) or the like, which may lead to delivery of improperly timed and potentially arrhythmogenic ETC signals. It is therefore desirable to have a method for determining proper timing of the delivery of ETC signals without unduly increasing the probability of delivering an improperly timed ETC signal caused by spurious noise detection or by detection of ectopic beats.
Co-pending U.S. Patent Application to Mika et al., Ser. No. 09/276,460, titled xe2x80x9cAPPARATUS AND METHOD FOR TIMING THE DELIVERY OF NON-EXCITATORY ETC SIGNALS TO A HEARTxe2x80x9d, filed Mar. 25, 1999 and assigned to the common assignee of the present application, the entire specification of which is incorporated herein by reference, discloses a method for timing the delivery of non-excitatory ETC signals to a heart using, inter alia, an alert window period for reducing the probability of delivering an improperly timed ETC signal to the heart due to spurious detection of noise or ectopic beats.
Co-pending U.S. patent application Ser. No. 09/338,649 to Mika et al., titled xe2x80x9cAPPARATUS AND METHOD FOR SETTING THE PARAMETERS OF AN ALERT WINDOW USED FOR TIMING THE DELIVERY OF ETC SIGNALS TO A HEART UNDER VARYING CARDIAC CONDITIONSxe2x80x9d, filed Jun. 23, 1999, the entire specification of which is incorporated herein by reference, discloses devices and methods for timing of delivery of ETC signals to the heart using, inter alia, a dynamically varying alert window period for event sensing.
Co-pending U.S. patent application Ser. No. 09/328,068 to Mika et al., filed Jun. 8, 1999, titled xe2x80x9cAPPARATUS AND METHOD FOR COLLECTING DATA USEFUL FOR DETERMINING THE PARAMETERS OF AN ALERT WINDOW FOR TIMING DELIVERY OF ETC SIGNALS TO A HEART UNDER VARYING CARDIAC CONDITIONSxe2x80x9d, the entire specification of which is incorporated herein by reference, discloses devices and methods for collecting patient data which is usable for the operation of a device for timing of delivery of ETC signals to the heart using, inter alia, a dynamically varying alert window period for event sensing.
It is noted that, while generally the term ETC signal refers to non-excitatory electrical signals applied to an excitable tissue, the terms ETC signal and CCM signal are interchangeably used throughout the present application to define non-excitatory cardiac contractility modulating electrical signals which are delivered to a heart. Similarly, while generally the term ETC device refers to a device which is capable, inter alia, of delivering non-excitatory contractility modulating electrical signals to an excitable tissue, the terms ETC device and CCM device are interchangeably used throughout the present application, to define a device which is capable, inter alia, of delivering non-excitatory cardiac contractility modulating electrical signals to a heart.
There is therefore provided, in accordance with a preferred embodiment of the present invention a method for controlling the delivery of a non-excitatory cardiac contractility modulating signals to a heart within a cardiac beat cycle. The method includes the step of sensing electrical activity in or about a first cardiac chamber to provide a first electrogram signal. The method also includes the step of detecting electrical events in the first electrogram signal. The method also includes the step of providing a first artifact window within the current beat cycle and detecting events occurring in the first electrogram signal within the duration of the first artifact window. The first artifact window starts at or after a trigger event representing the beginning of the current cardiac beat cycle. The first artifact window has a first artifact window duration. The method also includes the step of providing an alert window period within the current beat cycle. The alert window period has a first duration and is delayed from the trigger event. The method also includes the step of enabling the delivery of a cardiac contractility modulating signal to the first chamber of the heart within the current beat cycle in response to a first event detected in the first electrogram signal within the duration of the alert window period. The delivery of the cardiac contractility modulating signal is delayed from the time of detecting of the first event occurring within the duration of the alert window period by a first delay period. The cardiac contractility modulating signal has a cardiac contractility modulating signal duration. The method also includes the step of providing a refractory period within the current beat cycle, in response to the first event of the step of enabling for preventing the detection of electrical events within the duration of the refractory period. The refractory period has a refractory period duration, a beginning time and an ending time. The beginning time of the refractory period is delayed from the first event of the step of enabling by a second delay period. The ending time of the refractory period occurs at or after the termination of the cardiac contractility modulating signal. The method also includes the steps of applying the cardiac contractility modulating signal to the heart within the current beat cycle, and inhibiting the performing of the step of providing a refractory period and of the step of applying the cardiac contractility modulating signal, in response to detecting at least one inhibiting event within the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is an event associated with electrical activation of the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right ventricular event detected by a sensing electrode electrically coupled to the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right ventricular pacing command or an event synchronized therewith.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is an event associated with electrical activation of the right atrium of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right atrial event detected by a sensing electrode electrically coupled to the right atrium of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right atrial pacing command or an event synchronized therewith.
Furthermore, in accordance with another preferred embodiment of the present invention, the preventing of the step of providing a refractory period includes the step of stopping the sensing of the first electrogram signal within the duration of the refractory period.
Furthermore, in accordance with another preferred embodiment of the present invention, the preventing of the step of providing a refractory period includes the step of stopping the detecting of the electrical events in the first electrogram signal within the duration of the refractory period.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of detecting includes detecting electrical events based on a single threshold crossing criterion of the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of detecting includes detecting electrical events using a detection method based on one or more detection criteria selected from, the crossing of at least one threshold by the first electrogram signal, a slope criterion, a criterion based on one or more morphological parameters of the first electrogram signal and any combination thereof.
Furthermore, in accordance with another preferred embodiment of the present invention, the alert window period starts immediately after the first artifact window ends.
Furthermore, in accordance with another preferred embodiment of the present invention, the first delay period is equal to the second delay period.
Furthermore, in accordance with another preferred embodiment of the present invention, the first delay period is larger than the second delay period.
Furthermore, in accordance with another preferred embodiment of the present invention, the at least one inhibitory event includes a single event or any combination of events selected from the group of events consisting of, an event detected in the first electrogram signal within the time interval between the ending time of the first artifact window and the starting time of the alert window period, an event detected in the first electrogram signal within the duration of the alert window period after the time of detection of the first event of the step of enabling, and an event detected within the time interval starting after the end of the alert window and ending at the beginning time of the refractory period.
Furthermore, in accordance with another preferred embodiment of the present invention, the method further includes the step of inhibiting the delivery of a cardiac contractility modulating signal to the heart within the next beat cycle following the current beat cycle, in response to detecting in the first electrogram signal an event within the duration of a sensing time period starting after the end of the refractory period and ending at the end of the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the delivery of a cardiac contractility modulating signal to the heart within the current beat cycle was inhibited in the step of inhibiting due to an event detected in the first electrogram signal within the time interval between the ending time of the first artifact window and the starting time of the alert window period, or due to an event detected in the first electrogram signal within the duration of the alert window period after the time of detection of the first event of the step of enabling, and the method further includes the step of inhibiting the delivery of an cardiac contractility modulating signal to the heart within the next beat cycle following the current beat cycle, in response to detecting in the first electrogram signal an event within the duration of a time period starting after the end of the alert window and ending at the end of the first delay period.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of providing a first artifact window includes the steps of: if the trigger event is a sensed event associated with intrinsic activation of a second cardiac chamber, automatically selecting a first artifact window parameter set associated with the first artifact window, if the trigger event is an event associated with pacing of the second cardiac chamber, automatically selecting a second parameter set associated with the first artifact window, and determining the beginning time and the ending time of the first artifact window relative to the trigger event from the automatically selected parameter set.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right atrium of the heart, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a right atrial sensed event associated with intrinsic activation of the right atrium, the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right atrium, and each of the first parameter set and the second parameter set includes a first parameter representing the delay between the trigger event and the beginning time of the first artifact window and a second parameter representing the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right ventricle of the heart, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a sensed event associated with intrinsic activation of the right ventricle, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set of the first artifact window is identical to the second parameter set of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set of the first artifact window is different than the second parameter set of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the first artifact window starts at the time of detecting of the trigger event, the step of providing a first artifact window further includes the step of determining the duration of the first artifact window within the current beat cycle by automatically selecting a first duration value for the first artifact window if the trigger event is a sensed event associated with intrinsic activation of a second cardiac chamber, and automatically selecting a second duration value for the first artifact window if the trigger event is an event associated with pacing of the second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right atrium of the heart. The first duration value of the first artifact window is predetermined based on data obtained from cardiac beats of the heart in which the trigger event is a right atrial sensed event associated with intrinsic activation of the right atrium, and the second duration value of the first artifact window is predetermined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right atrium.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right ventricle of the heart. The first duration value of the first artifact window is predetermined based on data obtained from cardiac beats of the heart in which the trigger event is a sensed event associated with intrinsic activation of the right ventricle, and the second duration value of the first artifact window is predetermined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first duration value of the first artifact window is identical to the second duration value of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the first duration value of the first artifact window is different than the second duration value of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of providing an alert window period includes the step of determining the beginning time and the ending time of the alert window within the current beat cycle by automatically selecting a first alert window parameter set associated with the alert window period if the trigger event is a sensed event associated with intrinsic activation of a second cardiac chamber, automatically selecting a second parameter set associated with the alert window period if the trigger event is an event associated with pacing of the second cardiac chamber, and by computing the beginning time and the duration of the first artifact window from the selected parameter set.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart, the second cardiac chamber is the right atrium of the heart, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a sensed event associated with intrinsic activation of the right atrium, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right atrium.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart, the second cardiac chamber is the right ventricle of the heart, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a sensed event associated with intrinsic activation of the right ventricle, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the method further includes the steps of: initiating an artifact proximity interval, the artifact proximity interval starts at the time of detection of a proximity interval initiating event detected within the duration of the first artifact window and has an artifact proximity interval duration, and inhibiting the performing of the step of providing a refractory period and of the step of applying, in response to detecting in the first electrogram signal an event occurring within the duration of a part of the artifact proximity interval. The part does not overlap the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity artifact interval partially overlaps the alert window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the second step of inhibiting is performed when the event detected within the duration of the part of the artifact proximity interval occurs within a portion of the alert window period. The portion overlaps the artifact proximity interval.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of initiating an artifact proximity interval further includes the step of determining the duration of the artifact proximity interval by automatically selecting a first duration value for the artifact proximity interval if the trigger event is a sensed event associated with intrinsic activation of a second cardiac chamber, and automatically selecting a second duration value for the artifact proximity interval if the trigger event is an event associated with pacing of the second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart, the second cardiac chamber is the right ventricle of the heart, the first duration of the artifact proximity interval is determined based on data obtained from cardiac beats of the heart in which the trigger event is a right ventricular sensed event associated with intrinsic activation of the right ventricle, and the second duration of the first artifact window is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity interval initiating event is the first event detected within the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, more than one event is detected within the duration of the first artifact window and the proximity interval initiating event is the last event detected within the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, a plurality of events is detected within the duration of the first artifact window, and the proximity interval initiating event is a single event selected from the plurality of events.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity interval initiating event is an event detected within the duration of the first artifact window using a detection method based on an analysis of morphological parameters of the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the method further includes the step of providing a second artifact window period within the current beat cycle in response to a first timing event and ignoring all events detected in the first electrogram signal within the duration of the second artifact window period to avoid inhibiting the delivery of the cardiac contractility modulating signal within the current beat cycle by the detection of an expected electrical artifact signal within the duration of the second artifact window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart, the trigger event is an event associated with electrical activation of the right atrium of the heart, and the first timing event is an event associated with electrical activation of the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right atrial event detected by a sensing electrode electrically coupled to the right atrium of the heart, and wherein the first timing event is a right ventricular event detected by a sensing electrode electrically coupled to the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right atrial event detected by a sensing electrode electrically coupled to the right atrium of the heart, and the first timing event is a right ventricular pacing command or an event synchronized therewith.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right atrial pacing command or an event synchronized therewith, and the first timing event is a right ventricular event detected by a sensing electrode electrically coupled to the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right atrial pacing command or an event synchronized therewith, and the first timing event is a right ventricular pacing command or an event synchronized therewith.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of providing a second artifact window includes the step of computing, within the duration of the current beat cycle, the beginning time and the ending time of the second artifact window period based on the time of occurrence of the first timing event and on the value of a pair of predetermined reconstruction parameters.
Furthermore, in accordance with another preferred embodiment of the present invention, the beginning time of the second artifact window computed in the step of computing precedes the first timing event within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the beginning time of the second artifact window and the first timing event are identical within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first timing event precedes the ending time of the second artifact window within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the ending time of the second artifact window and the first timing event are identical within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first chamber is the left ventricle of the heart and the step of providing a second artifact window includes the steps of: if the first timing event is a sensed event associated with intrinsic activation of the right ventricle of the heart, automatically selecting a first parameter set associated with the second artifact window, if the first timing event is an event associated with pacing of the right ventricle of the heart, automatically selecting a second parameter set associated with the second artifact window, and determining the beginning time and the ending time of the second artifact window within the current beat cycle from the time of occurrence of the first timing event and from the automatically selected parameter set.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the first timing event is a right ventricular sensed event associated with intrinsic activation of the right ventricle, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the first timing event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set of the second artifact window is identical to the second parameter set of the second artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set of the second artifact window is different than the second parameter set of the second artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the method further includes the step of providing a third artifact window period within the current beat cycle in response to a second timing event and ignoring all events detected in the first electrogram signal within the duration of the third artifact window period to avoid inhibiting the delivery of a cardiac contractility modulating signal within the next beat cycle following the current beat cycle by the detection of an expected electrical artifact signal within the duration of the third artifact window period of the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart, the trigger event is an event associated with electrical activation of the right ventricle of the heart and the second timing event is an event associated with electrical activation of the right atrium of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right ventricular event detected by a sensing electrode electrically coupled to the right ventricle of the heart, and the second timing event is a right atrial event detected by a sensing electrode electrically coupled to the right atrium of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right ventricular event detected by a sensing electrode electrically coupled to the right ventricle of the heart, and the second timing event is a right atrial pacing command or an event synchronized therewith.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right ventricular pacing command or an event synchronized therewith, and the second timing event is a right atrial event detected by a sensing electrode electrically coupled to the right atrium of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the trigger event is a right ventricular pacing command or an event synchronized therewith, and the second timing event is a right atrial pacing command or an event synchronized therewith.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of providing a third artifact window includes the step of computing, within the duration of the current beat cycle, the beginning time and the ending time of the third artifact window period based on the time of occurrence of the second timing event and on the value of a pair of predetermined reconstruction parameters.
Furthermore, in accordance with another preferred embodiment of the present invention, the beginning time of the third artifact window computed in the step of computing precedes the second timing event within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the beginning time of the third artifact window and the second timing event are identical within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the second timing event precedes the ending time of the third artifact window within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the ending time of the third artifact window and the second timing event are identical within the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the first chamber is the left ventricle of the heart, and the trigger event is a trigger event associated with the right ventricle of the heart and wherein the step of providing a third artifact window includes the steps of: if the second timing event is a sensed event associated with intrinsic activation of the right atrium of the heart, automatically selecting a first artifact window parameter set associated with the third artifact window; if the second timing event is an event associated with pacing of the right atrium of the heart, automatically selecting a second parameter set associated with the third artifact window; and determining the beginning time and the ending time of the third artifact window within the current beat cycle from the time of occurrence of the second timing event and from the automatically selected parameter set.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the second timing event is a right atrial sensed event associated with intrinsic activation of the right atrium, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the second timing event is an event associated with pacing of the right atrium.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set associated with the third artifact window is identical to the second parameter set associated with the third artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set associated with the third artifact window is different than the second parameter set associated with the third artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of applying the cardiac contractility modulating signal includes the steps of: if the trigger event is a sensed event associated with intrinsic activation of a second cardiac chamber, automatically selecting a first parameter set associated with the cardiac contractility modulating signal; if the trigger event is an event associated with pacing of the second cardiac chamber, automatically selecting a second parameter set associated with the cardiac contractility modulating signal; computing the beginning time and the ending time of the cardiac contractility modulating signal within the current beat cycle from the automatically selected parameter set and from the time of detecting of the first event in the step of enabling; applying within the current beat cycle a cardiac contractility modulating signal having the beginning time and the ending time to the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, each of the first parameter set and the second parameter set includes a value of the first delay period and a value of the cardiac contractility modulating signal duration.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a right ventricular sensed event associated with intrinsic activation of the right ventricle, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right atrium of the heart. Furthermore, in accordance with another preferred embodiment of the present invention, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a right atrial sensed event associated with intrinsic activation of the right atrium, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right atrium.
Furthermore, in accordance with another preferred embodiment of the present invention, the step of providing a refractory period includes the steps of: if the trigger event is a sensed event associated with intrinsic activation of a second cardiac chamber, automatically selecting a first parameter set associated with the refractory period; if the trigger event is an event associated with pacing of the second cardiac chamber, automatically selecting a second parameter set associated with the refractory period; and, computing the beginning time and the ending time of the refractory period within the current beat cycle from the automatically selected parameter set and from the time of detecting of the first event in the step of enabling.
Furthermore, in accordance with another preferred embodiment of the present invention, each of the first parameter set and the second parameter set includes a value of the second delay period and a value of the refractory period duration.
Furthermore, in accordance with another preferred embodiment of the present invention, the first cardiac chamber is the left ventricle of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right ventricle of the heart, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a right ventricular sensed event associated with intrinsic activation of the right ventricle, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right ventricle.
Furthermore, in accordance with another preferred embodiment of the present invention, the second cardiac chamber is the right atrium of the heart, the first parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is a right atrial sensed event associated with intrinsic activation of the right atrium, and the second parameter set is determined based on data obtained from cardiac beats of the heart in which the trigger event is an event associated with pacing of the right atrium.
There is also provided, in accordance with another preferred embodiment of the present invention, a device for controlling the delivery of a non-excitatory cardiac contractility modulating signals to a heart within a cardiac beat cycle. The device includes sensing means for sensing electrical activity in or about a first cardiac chamber to provide a first electrogram signal, and for sensing electrical activity in or about at least a second cardiac chamber of the heart to provide at least a second electrogram signal; detecting means for detecting electrical events in the first electrogram signal and the at least second electrogram signal; means for providing a first artifact window within the current beat cycle, the first artifact window starts at or after a trigger event representing the beginning of the current cardiac beat cycle, the first artifact window has a first artifact window duration, and for detecting events occurring in the first electrogram signal within the duration of the first artifact window; means for providing an alert window period within the current beat cycle, the alert window period has a first duration and is delayed from the trigger event; means for enabling the delivery of a cardiac contractility modulating signal to the heart within the current beat cycle in response to a first event detected in the first electrogram signal within the duration of the alert window period, the delivery of the cardiac contractility modulating signal is delayed from the time of detecting of the first event occurring within the duration of the alert window period by a first delay period; means for providing a refractory period within the current beat cycle, in response to the first event, the refractory period has a beginning time and an ending time, the beginning time is delayed from the first event of the step of enabling by a second delay period, the ending time occurs at or after the termination of the cardiac contractility modulating signal, for preventing the detection of electrical events within the duration of the refractory period; means for applying the cardiac contractility modulating signal to the heart within the current beat cycle; and means for inhibiting the providing of the refractory period and for inhibiting the applying of the cardiac contractility modulating signal to the heart, in response to detecting at least one inhibiting event within the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes pacing means for pacing at least one cardiac chamber of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes implantable electrode means operatively connected to the pacing means, for applying pacing pulses to at least one chamber of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes storage means for storing data within the device.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes means for communicating data to and from the storage means.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes implantable electrode means operatively connected to the sensing means and to the means for applying, to perform the sensing in the heart and to apply the cardiac contractility modulating signals to the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes means for inhibiting the delivery of a cardiac contractility modulating signal to the heart within the next cardiac beat cycle following the current beat cycle, in response to detecting in the first electrogram signal an event within the duration of a sensing time period. The sensing time period starts after the end of the refractory period of a beat cycle in which a cardiac contractility modulating signal is delivered to the heart and ends at the end of the current beat cycle in which a cardiac contractility modulating signal is delivered to the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes means for inhibiting the delivery of a cardiac contractility modulating signal to the heart within the next cardiac beat cycle following the current beat cycle, in response to detecting in the first electrogram signal an event within the duration of a sensing time period starting after the end of the alert window and ending at the end of the first delay period, wherein the delivery of a cardiac contractility modulating signal to the heart within the current beat cycle was inhibited in the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the at least one inhibitory event includes a single event or any combination of events selected from the group of events consisting of: an event detected in the first electrogram signal within the time interval between the ending time of the first artifact window and the starting time of the alert window period; an event detected in the first electrogram signal within the duration of the alert window period after the time of detection of the first event of the step of enabling; and an event detected within the time interval starting after the end of the alert window and ending at the beginning time of the refractory period.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes: means for providing an artifact proximity interval, the artifact proximity interval starts at the time of detection of a proximity interval initiating event detected within the first artifact window and has an artifact proximity interval duration, and means for inhibiting the providing of the refractory period and for inhibiting the applying of the cardiac contractility modulating signal, in response to detecting in the first electrogram signal an event occurring within a part of the artifact proximity interval. The part does not overlap the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity artifact interval partially overlaps the alert window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity interval initiating event is the first event detected within the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, more than one event is detected within the duration of the first artifact window, and the proximity interval initiating event is the last event detected within the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, a plurality of events is detected within the duration of the first artifact window, and the proximity interval initiating event is a single event selected from the plurality of events.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity interval initiating event is an event detected within the duration of the first artifact window using a detection method based on an analysis of morphological parameters of the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes storage means for storing a plurality of parameter sets associated with at least one of the first artifact window, the alert window, the refractory period, and the cardiac contractility modulating signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes means for automatically selecting a parameter set associated with at least one of the first artifact window, the alert window, the refractory period, and the cardiac contractility modulating signal. The selecting is based on events selected from: events associated with pacing of the at least second cardiac chamber, events associated with intrinsic activation of the at least second cardiac chamber, and any combination thereof. There is further provided, in accordance with another preferred embodiment of the present invention, a device for controlling the delivery of a non-excitatory cardiac contractility modulating signals to a heart within a cardiac beat cycle. The device includes at least one sensing unit for sensing electrical activity in or about a first cardiac chamber to provide a first electrogram signal, and for sensing electrical activity in at least a second cardiac chamber to provide at least a second electrogram signal, at least one detecting unit adapted to detect electrical events in the first electrogram signal and in the at least second electrogram signal, a cardiac contractility modulating unit for delivering cardiac contractility modulating signals to the heart, and at least one controller unit operatively connected to the sensing unit, the detecting unit, and to the cardiac contractility modulating unit. The controller unit is adapted to provide a first artifact window within the current beat cycle. The first artifact window starts at or after a trigger event representing the beginning of the current cardiac beat cycle. The first artifact window has a first artifact window duration. The controller unit is adapted to detect events occurring in the first electrogram signal within the duration of the first artifact window. The controller unit is adapted to provide an alert window period within the current beat cycle for enabling the delivery of a cardiac contractility modulating signal to the heart by the cardiac contractility modulating unit within the current beat cycle in response to an enabling event detected in the first electrogram signal within the duration of the alert window period. The alert window period has a first duration and is delayed from the trigger event. The delivery of the cardiac contractility modulating signal is delayed from the time of detecting of the enabling event occurring within the duration of the alert window period by a first delay period. The controller unit is adapted to provide a refractory period within the current beat cycle in response to the enabling event, to prevent the detection of electrical events within the duration of the refractory period. The refractory period has a beginning time and an ending time. The beginning time of the refractory period is delayed from the enabling event by a second delay period. The ending time of the refractory period occurs at or after the termination of the cardiac contractility modulating signal. The controller unit is adapted to control the applying by the cardiac contractility modulating unit of the cardiac contractility modulating signal to the heart within the current beat cycle. The controller unit is adapted to inhibit the providing of the refractory period and the delivery of the cardiac contractility modulating signal within the current beat cycle, in response to detecting an inhibiting event within the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the device includes a memory unit operatively connected to the controller unit for storing data within the device.
Furthermore, in accordance with another preferred embodiment of the present invention, the device includes a communication unit operatively connected to the controller unit for communicating data to and from the memory unit.
Furthermore, in accordance with another preferred embodiment of the present invention, the device includes an implantable electrode operatively connected to the sensing unit for performing sensing in the first cardiac chamber. The device also includes at least one electrode operatively connected to the sensing unit for performing sensing in at least the second cardiac chamber. The device further includes at least one electrode operatively connected to the cardiac contractility modulating unit for applying the cardiac contractility modulating signals to the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the device includes a pacing unit operatively connected to the controller unit, for pacing at least one cardiac chamber of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes at least one implantable electrode operatively connected to the pacing unit for pacing at least one cardiac chamber of the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the detecting unit is included within the controller unit.
Furthermore, in accordance with another preferred embodiment of the present invention, the controller unit is adapted for inhibiting the delivery of a cardiac contractility modulating signal to the heart within the next cardiac beat cycle following the current beat cycle, in response to detecting in the first electrogram signal an event within the duration of a sensing time period starting after the end of the refractory period of a beat cycle in which a cardiac contractility modulating signal is delivered to the heart and ending at the end of the current beat cycle in which the cardiac contractility modulating signal is delivered to the heart.
Furthermore, in accordance with another preferred embodiment of the present invention, the controller unit is adapted for inhibiting the delivery of a cardiac contractility modulating signal to the heart within the next cardiac beat cycle following the current beat cycle, in response to detecting by the detecting unit in the first electrogram signal an event within the duration of a sensing time period starting after the end of the alert window and ending at the end of the first delay period, wherein the delivery of a cardiac contractility modulating signal to the heart within the current beat cycle was inhibited in the current beat cycle.
Furthermore, in accordance with another preferred embodiment of the present invention, the at least one inhibitory event includes a single event or any combination of events selected from the group of events consisting of: an event detected by the detecting unit in the first electrogram signal within the time interval between the ending time of the first artifact window and the starting time of the alert window period; an event detected by the detecting unit in the first electrogram signal within the duration of the alert window period after the time of detection of the first event of the step of enabling; and an event detected by the detecting unit within the time interval starting after the end of the alert window period and ending at the beginning time of the refractory period.
Furthermore, in accordance with another preferred embodiment of the present invention, the controller unit is adapted for providing an artifact proximity interval. The artifact proximity interval starts at the time of detection of a proximity interval initiating event detected within the first artifact window and has an artifact proximity interval duration. The controller unit is further adapted to inhibit the providing of the refractory period and to inhibit the applying of the cardiac contractility modulating signal, in response to the detecting, by the detecting unit, in the first electrogram signal an event occurring within a part of the artifact proximity interval. The part of the artifact proximity interval does not overlap the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity artifact interval partially overlaps the alert window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity interval initiating event is the first event detected within the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, more than one event is detected within the duration of the first artifact window, and the proximity interval initiating event is the last event detected within the duration of the first artifact window.
Furthermore, in accordance with another preferred embodiment of the present invention, a plurality of events is detected within the duration of the first artifact window, and the proximity interval initiating event is a single event selected from the plurality of events.
Furthermore, in accordance with another preferred embodiment of the present invention, the proximity interval initiating event is an event detected within the duration of the first artifact window using a detection method based on an analysis of morphological parameters of the first electrogram signal.
Furthermore, in accordance with another preferred embodiment of the present invention, the controller unit is adapted to provide a second artifact window period within the current beat cycle in response to a first timing event and to ignore all events detected in the first electrogram signal within the duration of the second artifact window period in order to avoid inhibiting the delivery of the cardiac contractility modulating signal within the current beat cycle by the detection of an expected electrical artifact signal within the duration of the second artifact window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the first timing event detected by the detecting unit is an event detected by the detecting unit in the second electrogram signal. The first timing event is associated with electrical activation of the at least second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the first timing event detected by the detecting unit is an event associated with pacing of the at least second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the first timing event detected by the detecting unit is a pacing command signal associated with pacing of the at least second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the second artifact window period provided by the controller unit partially overlaps the alert window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the controller unit is adapted to provide a third artifact window period within the current beat cycle in response to a second timing event, and to ignore all events detected in the first electrogram signal within the duration of the third artifact window period in order to avoid inhibiting the delivery of a cardiac contractility modulating signal within the next beat cycle following the current beat cycle by the detection of an expected electrical artifact signal within the duration of the second artifact window period.
Furthermore, in accordance with another preferred embodiment of the present invention, the second timing event is an event detected by the detecting unit in the second electrogram signal, the second timing event is associated with electrical activation of the second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the second timing event detected by the device is an event associated with pacing of the at least second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the second timing event detected by the device is a pacing command signal associated with pacing of the second cardiac chamber.
Furthermore, in accordance with another preferred embodiment of the present invention, the device further includes a memory unit operatively connected to the controller unit for storing a plurality of parameter sets associated with at least one of the first artifact window, the alert window, the refractory period, and the cardiac contractility modulating signal.
Finally, in accordance with another preferred embodiment of the present invention, the controller unit is adapted for automatically selecting from the plurality of parameter sets at least one parameter set associated with the at least one of the first artifact window, the alert window, the refractory period, and the cardiac contractility modulating signal. The selecting is based on at least one event selected from events associated with pacing of the at least second cardiac chamber, events associated with intrinsic activation of the at least second cardiac chamber, and any combination thereof.